Hydrosilylation is one of the most industrially useful reactions, and is used in, for example, functional group conversion and crosslinking reactions. For example, polymers having alkenyl functional groups at the ends of the molecular chains are cured by crosslinking using compounds having hydrosilyl groups as a curing agent. The resultant cured materials have superior heat resistance and durability. Furthermore, polymers having alkenyl groups at the ends of the molecular chains are reacted with compounds including hydrosilyl groups having crosslinkable silyl groups to produce polymers having the crosslinkable silyl groups at the ends of the polymers. Although these hydrosilylation reactions proceed by heating, a hydrosilylation catalyst is added in order to promote the reaction. The hydrosilylation catalysts include a radical initiator such as organic peroxides and azo compounds, and transition metal catalysts. In particular, it is known that transition metal catalysts can promote the hydrosilylation depending on the catalyst content.
On the other hand, living polymerization is generally known as a synthetic method that can synthesize polymers accurately. The living polymerization can not only readily control molecular weights and molecular weight distributions, but also produce polymers whose end structures are definite. Accordingly, the living polymerization is one of the useful methods to introduce functional groups to the ends of the polymers. Recently, some radical polymerization systems in which the living polymerization can also proceed have been found, and living radical polymerization has been studied extensively. In particular, atom transfer radical polymerization yields vinyl polymers having a small molecular weight distribution. In the atom transfer radical polymerization system, examples of the initiator include halogenated organic compounds or sulfonyl halides, and the catalysts include metal complexes containing an element in group 8, group 9, group 10, or group 11 in the periodic table, the element being contained as a central metal. (For example, see Matyjaszewski et al. J. Am. Chem. Soc. 1995, vol. 117, p. 5614, Macromolecules 1995, vol. 28, p. 7901, Science 1996, vol. 272, p. 866, and Sawamoto et al. Macromolecules 1995, vol. 28, p. 1721.)
However, since a transition metal complex used as the polymerization catalyst remains in the vinyl polymer produced by the atom transfer radical polymerization, the above methods cause problems of the coloring of the polymer and environmental safety, and influence the physical property of the polymer. Unfortunately, for example, in vinyl polymers having terminal alkenyl groups produced by the atom transfer radical polymerization, residual catalysts function as anticatalysts of the hydrosilylation reaction. Therefore, the residual catalysts inhibit the hydrosilylation, and a large amount of expensive hydrosilylation catalyst is necessary.
According to Japanese Unexamined Patent Application Publication No. 11-193307, a vinyl polymer produced by the atom transfer radical polymerization is purified by bringing the vinyl polymer into contact with an adsorbent such as aluminum silicate, thereby improving the hydrosilylation activity of the vinyl polymer. However, the improvement in the hydrosilylation activity is not sufficient with respect to the content of the adsorbent. In order to achieve sufficient hydrosilylation activity, the process requires a large amount of adsorbent. Unfortunately, the waste causes a high level of environmental load, and the use of the adsorbent causes an increase in purification cost.